1. Field of the Invention
The present invention relates to a display device.
2. Description of the Related Art
In a display device including a side-light type backlight unit, light entering an end surface of a light guide plate travels inside the light guide plate, and is reflected at an interface on a rear side of the light guide plate to exit from a front surface thereof (Japanese Patent Application Laid-open No. 2009-276531). In recent years, there has been a demand for reducing a region (frame) surrounding a display region of a display panel. In accordance therewith, the backlight unit is also demanded to have a narrower frame, and hence it is necessary to reduce brightness unevenness in the vicinity of a light-entering surface of the light guide plate. Therefore, an attempt has been made to cause refraction and expansion of light by forming irregularities or grooves at the end surface of the light guide plate (Japanese Patent Application Laid-open No. 2004-200072 and US 2004/0120139).
Depending on the shape of the irregularities or the grooves formed at the end surface of the light guide plate, the light traveling angle can be set to range from 0° (direction at right angle to the end surface) to an angle close to 90° (direction parallel to the end surface). When the light traveling angle is small, the light diffusion is insufficient, and hence a dark portion is formed between the end portion of the light guide plate and a light emitting diode (LED). In contrast, when the light traveling angle is large, the dark portion is eliminated, but a bright portion is generated depending on the angle. As described above, when the frame of the backlight unit is formed narrow, there has been a problem in that the brightness unevenness is generated.